The field of this invention relates generally to food containers which are convertible for other uses, and more particularly to potable liquid containers which are convertible into megaphones.
Attempts have previously been made to combine a megaphone with a container with various degrees of success. U.S. Pat. No. 4,125,218 to DeBoer, for example, discloses a megaphone cup device having a conical shape. The device is truncated and sealed at its smaller end with an end wall. Thus assembled, the cup can be used as a container for beverages, snack foods and the like. For use as a megaphone, the end wall is broken loose along a scored rim. Once removed, the structure becomes a permanent megaphone in that the end wall cannot be reinserted. Therefore, after being converted for use as a megaphone, the structure cannot again be used as a cup.
U.S. Pat. No. 2,507,843 to Wheeler discloses a food-carrying container apparatus which is convertible into a megaphone. The container is made of paper, is initially folded flat to have a triangular shape when viewed from the side, and in use is unfolded to form a cone-like structure. Thus unfolded, the container can be used to carry dry foods such as popcorn. To convert the container into a megaphone, the bottom is torn off the base to expose a smaller opening through which a human user can shout. The container is not suitable for use with liquids. Also, once converted into a megaphone, the apparatus cannot be re-converted back into a food-carrying container.
It is, of course, well known that a double-walled megaphone or speaker will be useful in sound amplification, see, e.g., U.S. Pat. No. 1,223,338, but such devices have not been incorporated in any manner into combined containers and megaphones. Moreover, such double-walled resonant chambers are often open at the large diameter end which can be very disadvantageous if attempting to use them as containers.
Several deficiencies reside in these existing containers. Some are not durable because they are made from thin deformable and destructible paper. They also lack thermal insulation, and the containers, therefore, permit heat transfer so any liquid held by the container will soon have the same temperature as the ambient environment. Additionally and very importantly, the container function must be destroyed in order to convert the container into a megaphone; the base of the container must be permanently removed.